CHAPTER XV. 



GROWTH, METAMORPHOSIS AND DEVELOPMENT. 

 Growth. 



OF all the problems in biology, one of the most difficult and most 

 engrossing is the development to constant type. From cells, which 

 externally can hardly be distinguished, we see develop a quail, an 

 oak tree, a butterfly or a man. In their evolution they always pass 

 through the same stages to the same ultimate forms which after a 

 progressive senescence, return to the eternal process of evolution. 



If we try to reduce these developmental processes to their sim- 

 plest terms, we find diffusion and swelling phenomena with the 

 formation of precipitate-membranes. 



E. F. RUNGE, who discovered carbolic acid in coal tar, and who 

 made the first anilin color, 1 published a book in 1855, which is one of 

 the most original scientific diversions I have ever seen. It is called 



"Der Bildungstrieb der Stoffe" 



(The formative instinct of matter) 



viewed in automatically developed figures 



By DR. F. E. RUNGE. 

 (Oranienburg. Printed by the Author.) 



The book consists of a collection of blotting paper leaves, upon 

 which various inorganic salt solutions were dabbed; they interacted 

 and gave colors by which the most remarkable figures were produced. 

 At first glance these seem to be lower forms of animal life, amebse 

 or rhizopodse, and the collection, just as HACKEL'S "Kunstformen 

 der Natur," might well serve as a text for designers, because it 

 offers such a multitude of suggestions with respect to color and 

 shape. All the pages of the collection were prepared by the author 

 himself (not printed) and are accompanied by a small amount of 

 text which explains the method of preparation. 



The explanation of these creations is easy to the author, who says 

 in one of his conclusions: 



1 [CHAS. LOWE is regarded as discoverer of phenol by the English, and Sir WM. 

 HENRY PERKIN is generally acknowledged, even by Germans, to be the discoverer 

 of the first anilin color, mauve. Tr.] 



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